The main reward you can obtain there are, one of the Artifacts, Dura's Conviction and Mystic Coat of Magic with a Wilder faction bonus. You can also earn substantial quantities of Gold and Hero's Essence.
Within the solar plane stands a vast valley which few adventurers have set foot in. Somewhere deep within the valley, is said to be an artifact of immense power. This artifact, however, is protected by a powerful order- “The Order of the Sun.” These protectors have devoted their lives to ensuring that this powerful artifact does not fall into the wrong hands. Thus, they built a great maze for which they use to hide it from the world. Only the worthy may claim what they seek here.
You can find 3 different levers on this map (yellow, red and blue). Flipping the switch will move tiles in the corresponding color up or down (it depends on the initial position of the tile), unlocking or blocking the path for the player.
You can find gold bags with various rewards, but they are mostly guarded by level 240 camps and these can be initially hard to beat.
Main reward chest (containing Dura's Conviction and Mystic Coat of Magic with Wilder faction bonus) is located in the middle of the map. The chest is blocked by 6 special tiles, to unlock them the player must beat 6 bosses camp surrounding the chest.
Bosses defending the chest (in suggested order, from the weakest to the strongest) are:
All of the bosses have level 290 and are completely immune to all crowd control abilities. While the Solar Plane is available after beating stage 17-4, you won't be able to complete it 100% for some time (for most players that would be chapters 20+). The reason for this is the 6 main bosses, immunity to crowd control effects makes them exceptionally hard to beat.
Viable options for beating the bosses sooner are:
- Kaz with her Death's Bite relic:
- The Firebringer and Icebringer relic combo:
Unfortunately rolling the right relics can be a boring task. You will probably have to restart the quest several times. Another option is just levelling up your heroes and generally bolstering your lineup.